Isomerization of c10-c14 hydrocarbons with fluorided metal-alumina catalyst

ABSTRACT

A method for preparing a hydrocarbon conversion catalyst by providing a composite composed of alumina having associated therewith a Group VIB, VIIB or VIII metal or compound and contacting the composite with an activator system comprising carbon monoxide and sulfuryl fluoride or thionyl fluoride. The catalysts so prepared are useful in such hydrocarbon conversion processes as isomerization, hydrocracking, reforming, alkylation, disproportionation, polymerization and hydrogenation.

United States Patent [191 Kravitz et al.

[111 3,843,747 [451 Oct. 22, 1974 ISOMERIZATION ()F C -C HYDRQCARBONSWITH 'FLUORIDED METAL-ALUMINA CATALYST [75] Inventors: Stanley Kravitz,Wiccopee; John H.

Estes; Robert M. Suggitt, both of Wappingers Falls, all of NY.

[73] Assignee: Texaco, Inc., New York, NY.

[22] Filed: Feb. 2, 1972 [21] Appl. No.: 223,031

Related 0.8. Application Data [62] Division of Ser. No. 49,896, June 25,1970, Pat. No.

[52] Cl. 260/683.68, 208/112, 260/672 T [51] Int. Cl. C07c 5/30 [58]Field of Search Zoo/683.68, 683.65

[5 6] References Cited UNITED STATES PATENTS 2,905,736 9/1959 BeldenZoo/683.68

2,908,735 10/1959 Huensel 260/683.68 3,078,323 2/1963 Kline et al.260/683.68 3,215,753 11/1965 Bloch et a1 260/683.68

Primary Examiner-Delbert E. Gantz Assistant Examiner-G. J. CrasanakisAttorney, Agent, or Firm-T. H. WhaleygC. G. 'Ries 5 7 ABSTRACT 10Claims, No Drawings ISOMERIZATION OF C -C HYDROCARBONS WITH FLUORIDEDMETAL-ALUMINA CATALYST This application is a division of applicationSer. No. 49,896 filed June 25, 1970, now US. Pat. No. 3,692,694.

BACKGROUND OF THE INVENTION This invention relates to the preparation offluorine containing catalysts and to their use in low temperaturehydrocarbon conversion processes. In one of its specific aspects, thisinvention relates to a method of preparing a catalyst comprising amember of Group VIB, VIIB or VIII of the Periodic Table, alumina andfluorine which is suitable for the conversion of hydrocarbons.

Fluorided catalysts are of interest for various processes includingisomerization, reforming, alkylation, hydrogenation, disproportionation,cracking, polymerization and hydrocracking. Heretofore, activation ofcatalyst bases or composites by fluoriding was undertaken employingaqueous hydrogen fluoride or vaporized boron or ammonium fluorides. Suchfluoriding techniques, however, by virtue of the fluoriding materialsemployed introduced various problems not the least of which includedhealth, handling and equipment corrosion. In some instances unwantedsurface deposits resulted from the treatment which interferred with thecatalysts ability to function. Moreover, such fluoriding techniquesdid-not lend themselves to the replacement of fluorine lost during hightemperature regeneration. Recently, other fluoriding compounds have beensuggested such as carbon tetrafluoride and sulfur tetrafluoride.However, these materials in addition to their costliness presentphysiological difficulties.

It is therefore an object of this invention to provide a method forcatalytically activating a composite material employing as components ofthe activator system fluoriding agents that introduce no equipmentcorrosion problems.

Another object of this invention is to provide a method for fluoridingcatalysts with an agent that is physiologically inert.

Yet another object of this invention is to provide a method forfluoriding catalysts with a fluoriding system employing as fluoridingagent materials heretofore considered inert.

Still another object of this invention is to provide a hydrocarbonconversion process undertaken in the presence of a catalyst prepared orregenerated in situ under non-corrosive conditions in a hydrocarbonconversion reactor.

Other objects and advantages will become apparent from a reading of thefollowing detailed description and examples.

SUMMARY OF THE INVENTION Broadly, this invention contemplates a methodof preparing a catalystcomprising a hydrogenating component, alumina andfrom about 0.5 to 15.0 weight percent fluorine which comprisescontacting alumina having associated therewith a hydrogenating componentselected from the group consisting of metals of Groups VIB, VIIB andVIII of the Periodic Table, their compounds and mixtures thereof with acombination of carbon monoxide and sulfuryl fluoride or thionyl fluorideat a temperature of from about 200 to 1200F.

According to our invention, catalytically active fluoride catalysts canbe prepared employing sulfuryl fluoride or thionyl fluoride, compoundsheretofore considered inert. It has been found that these compounds arerendered chemically reactive in the presence of a hydrogenating 7component comprising the metals and compounds of Groups VIB, VIIB andVIII and carbon monoxide such that an alumina composite can be activatedand provided with a chemically combined fluorine content of from about0.5 to 15.0, preferably 0.5 to 6.0 weight percent based on the catalyst.Catalytic activation under the conditions described herein is surprisinginasmuch as carbon monoxide has long been considered as a strong poisontowards Group VIII metal catalysts and particularly platinum catalysts.

The highly active hydrocarbon conversion catalysts contemplated hereinare prepared from an alumina composite activated with a combination ofcarbon monoxide and sulfuryl fluoride or thionyl fluoride. As mentionedabove, the alumina has associated therewith as a component of thecomposite a member selected from the group of metals of Groups VIB, VIIBand VIII of the Periodic Table exemplified by chromium, molybdenum,tungsten, rhenium, cobalt, nickel, platinum, palladium, ruthenium andrhodium. Combinations of metals are also contemplated such asplatinumrhenium, nickel-tungsten and cobalt-molybdenum. The

member may be present on the catalyst as metal or as a compound such asthe oxide, sulfide or salt such as the sulfate. Preferably we employ amember having hydrogenating activity such as the metals of Group VIIIand we particularly prefer platinum and palladium. In general, thecatalyst may contain a member of Groups VIB, VIIB or VIII in amounts offrom 0.01 to 30 weight percent calculated as weight of metal. When GroupVIII members such as platinum, palladium, rhodium and ruthenium areemployed as composite components we preferably employ from 0.1 to 2.0weight percent.

Combinations of metals such as nickel and tungsten are employed ingreater amounts as for example 20 to 30 weight percent.

Aluminas in various forms may be used in this invention and particularlythose aluminas having replaceable surface hydroxyl groups and surfaceareas of 50 to 800 square meters per gram using the BET method. Includedwithin our definition of alumina, we mention for example eta-alumina,gamma-alumina, silica-stabilized alumina, i.e., aluminas containingapproximately 5 weight percent SiO thoria-alumina, zirconia-alumina,titania-alumina and aluminosilicates having surface areas of from 600 to800 square meters per gram. Preferably we employ aluminas having surfaceareas of from 50 to 400 square meters per gram and particularly etaandgamma-alumina. Suitable composites contemplated for contacting with ourfluoriding system include commercially available materials includingplatinumalumina and platinumrhenium-alumina reforming catalysts,chrome-alumina dehydrogenation catalysts and nickel-tungsten-alumina,nickel-tungsten-silicaalumina hydrogenation catalysts. The compositesare prepared by techniques well known to the art. Illustratively, ametal, such as platinum, is provided to the composite by impregnatingactive alumina with an aqueous solution of chloroplatinic acid andethylene diamine followed by drying and calcining at about 1050F. for 2hours thereby providing a platinized alumina composite. Where palladiumis contemplated, it

may similarly be introduced by providing a palladium tetramine complexas by dissolving palladium chloride in hydrochloric acid, diluting withwater and concentrated ammonium hydroxide followed by heating at 140F.with stirring for about 30 minutes until the precipitate originallyformed is dissolved. The resulting solution is cooled and added to thealumina and after thorough mixing the alumina is dried at about 300F.and thereafter calcined at elevated temperatures of from 800 to 1200F.for periods of at least 2 hours. Nickel oxide on alumina can be preparedby adding an aqueous solution of nickel nitrate to alumina attemperatures of from 80 to 200F. and calcining the dried composite at800F. In a similar manner, Group VIB and VIIB members are provided tothe composite by impregnation with soluble salts of these metals,followed by calcination at 600 to 1,200F. for several hours.

In accordance with our invention, a composite as hereinabove defined iscontacted with a combination of carbon monoxide and sulfuryl fluoride orthionyl fluoride to introduce to the final catalyst about 0.5 to 15.0weight percent chemically combined fluoride. Fluoriding in accordancewith this invention enhances the acidity of the treated compositethereby promoting the catalysts activity and improving its selectivity.Moreover, fluoriding provides the catalyst with activity at lowertemperatures where the unfluorided composite would be inactive.

The mole ratio of carbon monoxide to fluoride compound during thecontacting stage can vary from 0.1 to 100 moles of carbon monoxide permole of fluoride compound and preferably within the range of l to molesof carbon monoxide per mole of fluoride compound..Mole ratios of carbonmonoxide less than 0. l :l are undesirable because there is inefficientutilization of the fluoride compound and ratios above 100:1 areunnecessary because this greatly exceeds the optimum requirements ofcarbon monoxide consumption. The

activating combination of carbon monoxide and sulfuryl fluoride orthionyl fluoride may be introduced to the composite separately or asmixed gaseous streams and the gaseous activator components are permittedto flow through and over the composite. During contacting, the compositeis generally maintained at a temperature of from 200 to 1,200F. andpreferably at a temperature of from about 600 to 900F. Depending on theactivating temperature employed and the weight percent fluorine to beintroduced to the composite, contact times ranging from one-half to 24hours are employed. In view of the noncorrosive nature of the fluoridecompounds, the catalyst can be prepared in situ in a hydrocarbonconversion reactor by passing a stream of carbon monoxide and thefluoride compound to the vessel directly containing the composite. Theeffluent from the reactor during activation contains hydrogen sulfide,water and unreacted components and activation can be consideredessentially complete when no further hydrogen sulfide is detectable inthe effluent. In general, hydrogen sulfide cessation indicates afluorine content of about 4 weight percent. However, fluoriding may beterminated prior to cessation of hydrogen sulfide evolution to providefluoride contents as low as 0.5 weight percent or fluoriding may becontinued past this point so as to provide the catalyst with a fluorinecontent of up to at least 15.0 weight percent, and preferably up to 6.0weight percent.

As mentioned above, the composite is contacted with a combination ofcarbon monoxide and sulfuryl fluoride or thionyl fluoride. In theabsence of the aforementioned Group VIB, VIIB and VIII members as acomponent of the composite the fluoride compound is chemically inactive,particularly at temperatures of 900F. and below, and the alumina ismerely provided with absorbed fluoride compound and not chemicallycombined fluorine. Merely absorbing the compound onto the composite doesnot provide or promote activity nor improve selectivity. Unexpectly,composites of alumina associated with a Group VIB, VIIB or VIII metal asdescribed above when contacted with a combination of carbon monoxide andsulfuryl fluoride or thionyl fluoride in some manner unknown toapplicants permits reaction between the heretofore considered inertfluoride compounds and the composite such that chemically combinedfluorine is introduced to the composite thereby providing thecontemplated catalytically active material. Contacting as set out aboveis broadly undertaken at a temperature of at least 200 and up to 1,200F.Preferably, initial contacting of the composite, carbon monoxide andfluoride compound is conducted at temperatures .of at least 450F.thereby initiating rapid fluoriding of the composite. Upon reaching afluoride content of about 0.5 weight percent, subsequent contactingtemperatures as low as 200F. can be employed. However, at the lowertemperatures the reaction is slow and results in inefficient use offluoride compound. Initial or subsequent contact temperatures below200F. are generally insufficient to provide adequate reaction rates orhighly active catalysts useful for commercial size operations in thatfluoride levels of less than 0.5 weight percent result. In our highlypreferred embodiment all contacting is conducted at temperatures of fromabout 600 to 900F.

Ascontemplated herein, the inventive concept includes both initialactivation and subsequent regeneration of the fluorided catalysts. Itwill be appreciated that during the course of hydrocarbon conversion,feedstocks employed may in some instances contain materials such ascombined nitrogen in amounts exceeding 30 ppm or such other materials assulfur or carbonaceous deposits which in the course of operation causethe catalyst to become deactivated. These deactivating materials areremoved from the catalyst by a hydrogen strip or a controlled oxidation.The catalyst surface is then exposed to a regenerating procedure bycontacting with the combination of carbon monoxide and fluoride compoundin a manner described above.

The catalyst prepared by our invention can be produced in pellet,granular, bead or pulverulent form to facilitate its use in fixed beds,moving beds or fluidized solid beds as is well known in the art. Duringthe course of catalyst activation or regeneration, the effluent from thehydrocarbon conversion reactor consists largely of hydrogen sulfide,water, sulfur dioxide, carbon monoxide and unconverted fluoridecompound. Any unconverted fluoride compound and excess carbon monoxidemay be recycled.

The catalyst prepared herein is highly active for hydrocarbon conversionat relatively low temperatures of from 200 to l,000F. and findsapplication in a broad spectrum of conversion processes includinghydrocracking, selective hydrocracking, hydroisomerization,disproportionation, alkylation, polymerization, reforming andhydrogenation. In general, the hydrocarbon feedstocks contain less than30 ppm nitrogen and are converted in the presence of our catalyst attemperatures recited above.

Catalysts prepared according to our invention are admirably suited toconvert a wide range of hydrocarbon materials. Illustratively, fluoridedplatinized aluminas are highly active for hydrocracking andhydroisomerizing such charge materials as waxes, slack wax and middledistillate oils at temperatures of 550 to 800F., at pressures of 300 to750 pounds per square inch gauge, liquid hourly space velocities of 1 to20 and in the presence of hydrogen. In general, catalysts containinglower fluorine contents require the higher conversion temperatures forequivalent rates of reaction. Selectivity for isomerization of normal Cto C paraffins is improved at the lower temperatures. Aromatics can behydrogenated and lubricating oil fractions can be modified to improveviscosity index and pour point. Fluorided aluminas having metalcompounds such as the oxides associated therewith, exemplified bychromia and molybdena fluorided aluminas, show substantial activity fordisproportionation of aromatics as for example the conversion of tolueneto benzene and xylene at 750 to l,000F. The catalysts are active foralkylation of aromatics and aliphatics and polymerization of olefins attemperatures of 200 to 400F. and pressures of 300 to 800 p.s.i.g. Thefluorided catalysts are active for I hydrocarbon conversions atconsiderably lower temperatures than the non-fluorided composite. Forexample, fluorided platinized alumina permits isomerization of C to Cn-paraffins at the 600F. range whereas the non-fluorided composite isinactive at temperatures below 800F.

In order to more fully illustrate the nature of our invention and mannerof practicing the same, the following examples are presented:

EXAMPLE I 150 cc. of commercially available 0.47 weight percent platinumon eta-alumina is calcined at 800F. for 2 hours in an inert atmosphere.The temperature is reduced to 700F. and sulfuryl fluoride is introducedalong with carbon monoxide to the composite at the rate of 4 liters perhour of sulfuryl fluoride and 16 liters per hour of carbon monoxide fora period of 4 hours. The fluorine content of the catalyst isapproximately 3 weight percent.

EXAMPLE II 150 cc. of commercially available 0.47 weight percentplatinum on eta-alumina is calcined at 800F. for 2 hours in a hydrogenatmosphere flowing at the rate of liters per hour. After reducing thetemperature to 700F., thionyl fluoride and carbon monoxide areintroduced to the composite at the rates, respectively, of 4 liters perhour and 16 liters per hour for a period of 4 hours. The fluorinecontent of the catalyst is approximately 3 weight percent.

From the foregoing, it can be seen that we have provided a significantlyuseful process for the preparation of a catalyst useful in theconversion of hydrocarbons. Our catalyst is particularly useful in theisomerization of isomerizable hydrocarbons especially paraffinichydrocarbons in the C to C range. Our catalyst can also be used inalkylation processes without varying the manipulative procedures toaccommodate the catalyst prepared by our invention. It is seen that ourprocess can be performed in situ, i.e., within the hydrocarbonconversion reactor itself and does not necessitate withdrawal ofcatalyst from the vessel for transfer to the hydrocarbon conversionreactor with the attendant problem of subjecting the catalyst tomoisture. It should be further noted that our process can be performedto regenerate a spent catalyst by first heating the spent cata lyst todecarbonize the catalyst and then treating in the manner of ourinvention. Our process can be performed without the use of expensivechemicals, high pressures or temperatures and is thus suited for commercial operation. Our catalyst can. contain any one of theaforementioned metals, for example, platinum, palladium, ruthenium andrhodium depending upon the choice of the particular operator, theavailability of the metal, etc. The activation of the catalyst basescontain ing any of these metals proceeds essentially in the same way ofactivation of alumina base catalyst containing another metal of thegroup. Thus the manipulative procedure does not substantially vary fromone metal to the other.

The terms and expressions which have been used herein are terms ofdescription and not of limitation as there is no intention in the use ofsuch terms and expressions of excluding any equivalents of the featuresshown and described or portions thereof as it is recognized that variousmodifications are possible within the scope of the invention.

We claim:

ll. An isomerization process which comprises contacting a feedstockcontaining C to C hydrocarbons at a temperature of from 200 to l.,000Fin the presence of hydrogen with a catalyst comprising a hydrogenatingcomponent, alumina and from about 0.5 to 15.0 weight percent fluorine,said catalyst prepared or regenerated by contacting alumina havingassociated therewith a hydrogenating component selected from the groupconsisting of the metals, oxides, sulfides and salts of the metals ofGroups VIB, VIIB and VIII of the Periodic Table and mixtures thereof,with a combination of carbon monoxide and a fluoride compound selectedfrom the group consisting of sulfuryl fluoride and thionyl fluoride at atemperature of from about 200 to 1,200F.

2. A process according to claim 1 wherein said hydrogenating componentis present in said catalyst in an amount of from 0.01 to 30.0 weightpercent calculated as weight of metal.

3. A process according to claim ll wherein said component is selectedfrom the group consisting of platinum, palladium, rhodium and rutheniumand where said component is present in said catalyst in an amount offrom 0.1 to 2.0 weight percent.

4. A process according toclaim ll wherein said component comprisesplatinum and rhenium.

5. A process according to claim 1 wherein said fluoride compound issulfuryl fluoride.

6. A process according to claim 1 wherein said fluoride compound isthionyl fluoride. I

7. A process according to claim 1 wherein the mole ratio of said carbonmonoxide to said fluoride compound is from 0.121 to :1.

8. A process according to claim ll wherein said temperature is from 600to 900F.

9. A process according to claim 1 wherein said alumina is eta-alumina. i

10. A process according to claim 1 wherein said'alumina isgamma-alumina.

1. AN ISOMERIZATION PROCESS WHICH COMPRISES CONTACTING A FEEDSTOCKCONTAINING C10 TO C14 HYDROCARBONS AT A TEMPERATURE OF FROM 200* TO1,000*F IN THE PRESENCE OF HYDROGEN WITH A CATALYST COMPRISING AHYDROGENATING COMPONENT, ALUMINA AND FROM ABOUT 0.5 TO 15.0 WEIGHTPERCENT FLUORINE, SAID CATALYST PREPARED OR REGENERATED BY CONTACTINGALUMINA HAVING ASSOCIATED THEREWITH A HYDROGENATING COMPONENT SELECTEDFROM THE GROUP CONSISTING OF THE METALS, OXIDES, SULFIDES AND SALTS OFTHE METALS OF GROUPS VIB, VIIB AND VIII OF THE PERIODIC TABLE ANDMIXTURES THEREOF, WITH A COMBINATION OF CARBON MONOXIDE AND A FLUORIDECOMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURYL FLUORIDE ANDTHIONYL FLUORIDE AT A TEMPERATURE OF FROM ABOUT 200* TO 1,200*F.
 2. Aprocess according to claim 1 wherein said hydrogenating component ispresent in said catalyst in an amount of from 0.01 to 30.0 weightpercent calculated as weight of metal.
 3. A process according to claim 1wherein said component is selected from the group consisting ofplatinum, palladium, rhodium and ruthenium and where said component ispresent in said catalyst in an amount of from 0.1 to 2.0 weight percent.4. A process according to claim 1 wherein said component comprisesplatinum and rhenium.
 5. A process according to claim 1 wherein saidfluoride compound is sulfuryl fluoride.
 6. A process according to claim1 wherein said fluoride compound is thionyl fluoride.
 7. A processaccording to claim 1 wherein the mole ratio of said carbon monoxide tosaid fluoride compound is from 0.1:1 to 100:1.
 8. A process according toclaim 1 wherein said temperature is from 600* to 900*F.
 9. A processaccording to claim 1 wherein said alumina is eta-alumina.
 10. A processaccording to claim 1 wherein said alumina is gamma-alumina.